This invention relates generally to an agricultural harvesting machine, and more particularly, to a rotary impeller for a tailings conveyor of a harvesting machine having blades configured and shaped for providing desired tailings conveying and threshing functions.
Typically, an agricultural harvesting machine such as a combine gathers crop from a field and transports the crop by means of a feeder house to a threshing and separating device located inside the combine. Generally, threshing refers to removing grain, beans, seeds or kernels, hereinafter referred to as just grain, which are desired to be collected, from husks, cobs, pods, stems, and other portions of the plants being harvested, which are to be discarded. The threshing and separating device delivers the crop to the cleaning system of the combine, which includes a plurality of sieves. An upper sieve allows clean grain and some material other than grain (MOG) to fall through it, and a lower sieve is adjusted so that only clean grain is allowed to pass through it. The material including the clean grain and MOG that falls through the upper sieve, but does not pass through the lower sieve, is called tailings. In many cases it is desired for this material to be threshed and/or cleaned again.
Prior methods accomplish the threshing and/or cleaning of the tailings by conveying them to one side of the combine with an auger. The tailings are then carried by a conveyor, typically a paddle and chain conveyor, back to the combine threshing mechanism. Some combines have used a rethreshing device which is separate from the threshing system which helps save capacity on the threshing system by rethreshing the tailings separately from new crop coming into the combine. The auger feeds material into the rethreshing device and then the material is conveyed back to the cleaning system. Both single impeller/blowers and augers have been used to convey this material back to the cleaning system. These rethreshing devices are usually convertible, enabling the operator to manipulate the machine to be more or less aggressive, depending on the vulnerability of the grain to damage, during processing.
Prior methods for conveying the tailings material are inefficient in terms of throughput capacity and power consumption. Some known embodiments have resulted in large conveying devices that tend to limit access to both the combine and the conveying device for maintenance and conversion.
Therefore, what is needed is a more efficient means for conveying tailings, which overcomes many of the limitations and shortcomings set forth above, and which provides a desired threshing function.